This invention is generally directed to an attachment system for a cable puller. Cable pullers are often used to pull cables or wires, for example, telephone wires, optical cables, or electrical service cables, through conduit. A typical cable puller generally includes a base and a boom extending from the base. An elbow is provided at the free end of the boom and an adaptor is mounted to the elbow. The adaptor generally includes brackets for attaching the adaptor to the elbow and a cylindrically-shaped extension for attaching the adaptor to the conduit through which the cable is pulled.
A first example of a prior art adaptor is shown in FIG. 1. The adaptor 20 includes a bracket 21 and a cylindrically-shaped extension 22 extending therefrom. The extension 22 is designed to fit within the end of the conduit through which the cable is to be pulled. The outer diameter of the cylindrically-shaped extension 22 is therefore slightly smaller than the inner diameter of the conduit to allow the extension 22 to nest within the conduit. A plurality of adaptors 20 having various diameters are provided so that the adaptor 20 can be sized to the conduit. Although an adaptor having an extension with a much smaller diameter could nest within the conduit, the adaptor would then restrict the opening through which the wire/cable was to be pulled.
A second example of a prior art adaptor is shown in FIG. 2. The adaptor 30 includes a bracket 31 and a cylindrically-shaped extension 32 having threads on the internal surface thereof. The adaptor 30 is mounted to a conduit by engaging the threads of the extension 32 with threads on the outer surface of the conduit. In order for the threads of the extension 32 to engage with the threads of the conduit, the adaptor 30 must be sized to the conduit. Thus, as with the adaptor 20 shown in FIG. 1, several adaptors 30 are needed to accommodate a variety of conduit diameters.